Belgian authorities are hoping they have made a major breakthrough in solving a heist of diamonds and gems worth some 40 million euros ($42 million) at Brussels' international airport two years ago.

During a series of raids early Monday, authorities made several arrests and were analyzing goods that could be linked to the theft, which ranks as one of the biggest diamond heists in memory. Authorities refused to say how many were arrested.

On Feb. 18, 2013, eight gunmen cut a fence around Brussels airport, drove onto the tarmac where an armored car was transferring the gems onto a Zurich-bound airplane and drove off again with the loot.

So far, 14 have been charged in the case but most of the diamonds are still missing.